Electric telephone



(No Model.)

H. B. PORTER.

ELECTRIC TELEPHONE. No. 269,879. Patented Jan. Z, 1883-.v

UNITED STATES PATENT EEICE.

ELECTRIC TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 269,879, dated January2, 1863.

Application filed June 1, 1882. (No model.)

To all whom it may concern:

Be it known that I, HENRY B. PoR'rER, of Chicago, in the State ofillinois, have invented certain new and useful Improvements in ElectricTelephones, of which the following is a specitcation.

The improvement consists in a modification ofthe instrument shown inLetters Patent No. 246,552, dated August 30, 1881, granted to me forsound-transmitter.

The accompanying drawings illustrate the invention. Figure l is aninside view ofthe instrument with the front plate and diaphragm removed.Fig. 2 is a central cross-section on line x .cof Fig. l. Fig. 3 is afront view ofthe speaking-tube and face-plate. Fig. el. is a front viewof the diaphragm detached.

A represents the cup or chamber of the instrument. B is the face-plate,having a conical orifice in the sa me, forminga mouth-piece. Between thechamber and face-plate, the diaphragm C is secured by its edges. Behindthe diaphragm are th-ree or more radially-arran ged springs. D, carryingat theirinner ends metal cups with blocks of carbon, a, three or moreplatinum points, b b b, secured to the ends of the prongs of a metalplate, c, having' prongs corresponding in number with the points b,which are thereby held in contact with the blocks of carbon. The prongedplate, instead of being supported as shown in my said former patent, issupported on a central pin, b', soldered to the center of' the diaphragmand to the center ofthe said plate, andthe points b do not rest againstthe diaphragm, 'as in my said former patent. The back plate, guidepins,and spiral spring, whose tension serves to hold the pronged plate, withits contacts, against the diaphragm, as shown in my said former patent,are thus dispensed with; and to the springs D are attached. at l1.,three radial aims, i, extending from a'central support, L, through whichan adjusting-screw, H, passes loosely, so as to turn in the same. Thescrew is shouldered against the central support, h', on one side, andhas a small nut, a, ou the end against the opposite side. Theadjustingscrew passes through a nut, N, fixed in the rear Wall of thechamber, and by turning the screw in or out the central support and arms'i may be moved toward or from the diaphragm, and through the connectionof these arms with springs D the carbons a are similarly adjusted ou thepoints b. The adjusting-screw also passes through an outsidetightening-uut, N', by tightening which against nut Nthe adjusting-screwis tightened or held fast at any desired point of adjustment.

The electric circuit is made in the transmit ter as follows: One wire,E, is attached to the. central pin, b', `and is in electrical contact,through said pin and the pronged plate, with all the points b. The otherwire, K, is connected with all ofthe springs D, and through them is inelectrical contact with all ofthe carbons.

ln my said former patent 11o means for adjusting thecarbons toward andfrom the points b are provided; also, the points b extend through theprongs and are pressed against the diaphragm by a small coil-spring,which to a slight extent impedes the vibrations ofthe diaphragm.

rlhe present invention providesfor adjusting the carbons and supportsthe pronged plate points I) do not rest against the diaphragm, but aresupported by the prongs ofthe pronged plate, which affords aslightly-yielding support to said points. By this arrangement thecarbons may be adjusted and the amplitude ofthe voice-vibrations ofthediaphragm is preserved and more perfectly'transmitted to the electriccurrent so connected wit-h the diaphragm.

1. ln asound-transmitter, threeormore platif num points, b,supportedupon apronged plate, c, connected by a pin, b', to the diaphragm, andsupported thereby, in combination with acorresponding number ot' carbonsin adjustable contact therewith and connected in the electric circuit,substantially in the manner shown.

2. The transmitterconsisting of case A B, diaphragm C, radially-arrangedsprings D, carrying the carbons, arms c', connecting with springs D andadjusting-screw H, pronged plate c, carryingplatinum points b, and connected to and supported upon the diaphragm by a pin, b', and wire E, allcombined and arranged substautially as shown and described.

HENRY B. PORTER.

Witnesses:

J oHN H. WHIPPLE, W. O. RoBrNsoN.

and wire E upon the diaphragm; also, thev

